Loud-speaker unit



. June 21 1927'.

. 1,633,179 G. F. C. HOUGHTON LOUD SPEAKER UNIT Filed May '7. 1925 11 Z6 ll 2 2221 28. ma H I" 4 I 21 I l x 22 15 INVENTOR 5201921 ffiuyfilan "ATTORNEY Patented June 21, ldZZ Persia GEORGE C. HOUGFHTON, OF FLjJ'SHING, NEW YORK.

Loon-SPEAKER UNIT.

Application filed May 7,

The invention relates to electrical receiver apparatus for amplifying sound, more especially to the type generally termed loud speaking receivers, and especlally of the arrangement in which there is employed a permanent magnet of substantial proportions carrying a pole piece surrounded by a solenoid, said pole piece being designed to attract one end of an armature lever whose other end is connected with a diaphragm.

The invention has for its object, in a receiver of the aforesaid type, to so mount the armature lever that the same shall be sufficiently removed from the permanent magnet portion of the apparatus or constructed to 'avoid being subject to any appreciable magnetic pull therefrom except by the solenoid pole piece; and, furthermore, that the armature lever shall be in a substantially balanced and neutral condition. A. further object of the invention resides in a mounting wherein a substantially acoustically inert, non-metallic material is employed for supporting the armature lever and diaphragm so that no undesirable vibrations will be communicated to the latter, and: with which said lever is connected. The invention has for a still further object a construction wherein the respective armature and magnet portions-of the apparatus are in the nature of independent units and-admit of ad ustment relatively to each other so that the free end of the armature'may be adjusted with great nicety relatively to its cooperating pole piece.

' The nature of the invention, however, will best be understood when described in connection with the accompanying drawings, m which Fig. 1 is a front elevation of the rece1ver unit with a portion of the supporting frame broken away to more clearly set forth the support arrangement for the armature lever.

Fig. 2 is a horizontal sectlon taken on the line- 2-2, Fig. 1, and looking in the .direc tion of the'arrows.

Fig. 3 is an end view of the armature lever and mounting; and Figs. 4 and 5 are enlarged vertical transverse sections taken on the lines 4-4 and 5-5, respectively, Fig. 3, and looking in the direction of the arrows.

Referrin to the drawings, 10 designates a suitable rame comprising an annular portion 11; and isadapted to hold rigidly, as by means of suitable clamping screws 12, a permanent magnet 13 one leg of which 1s 1925. Serial No, 28,573;

somewhat shorter than the other. The said frame is preferably of a moulded composition as of any of the various well-known condensation products and which are substandesigned to carry a diaphragm member 20 of any suitable material, preferably nonmetallic and of a more or less acoustically inert composition. This diaphragm is designed to be vibrated by an armature lever 21, one end of which is rigidly connected therewith, for example, by means of a screw 22 and intermediate,adjustable nut 23, the other end of the lever being located in close proximity to the pole piece 14 for attraction thereby to vibrate said diaphragm in accordance with the fluctuations of current received by the solenoid 15. This armature lever may be also of .substantially acoustically inert material except, of course, at the end opposite the pole piece to be attracted thereby.

In accordance with the present invention, the lever-21 is arranged to be maintained in a substantially balanced and neutral ebndition to be responsive to the slightest variation in the attraction thereon; and is suit ably held to the frame 10. To this end, the

said armature lever is rigidly secured to a plvot bar 25, also of acoustically inert material and mounted to rock on a bracket 26 secured to the underside of the frame 10 at the ring 11, and is recessed at its lower edge to allow the lever 21 to pass thru for attachment to the said pivot bar 25. The latter rocks in front of the bracket 26, which bracket is provided for this purpose with two pivota points or knife edges 27 extending outwardly therefrom and to which the bar 25 is held. In order to retain said bar in position relatively to the bracketi26 for this ivotal movement thereon, and to efiect a alanced neutral condition of the lever 21 which is carried by said bar, 'two oppositely acting spring members 28 and 29 upwardly directed arm and a downward-' 1y directed arm 31 upon which the respective spring ends bear, the contacting portions being preferably roughened. To insure a fixed position of the said springs 28 and 29, their corresponding opposite ends are ar ranged to be firmly secured to the bracket 26 as thru respective sockets 32 and 33 provided'thei'ein and into which the corresponding spring ends are fitted. In this manner. the pivotal points while determining the axial line about which the pivot bar rocks,

afiord also a minimum and sensitive bearing surface so that great freedom of motion and consequent quickness of action results, the necessary accuracy of movement and position being preserved by the said points w"or knife edges which, as well, prevent undesirable and detrimental translation or angular movement. A pair of springs directed oppositely, as set forth, balances'the lever so that the same is in a most sensitive condition f or responding to variations in the magnetic attraction of its pole piece.

Furthermore, in view of the construction aforesaid embodying substantiallytwo inde-. pendent units, viz: the magnet unit with solenoid and the diaphragm and lever unit, assembly and adjustment in the initial set-up are greatly facilitated-the latter unit sliding readily along the former and being con veniently clamped thereto by the screws 12 when the most suitable position of pole piece relatively to the armature has been determined.

I claim 1. An electric loud speaking receiver unit, comprising a permanent magnet having poles located in proximity to each other, a frame secured thereto, a solenoid about one of the poles of the magnet, a diaphragm carried by said frame, an armature lever having. one end rigidly connected with the said diaphragm and its other end under the influence of the said solenoid pole piece, a bracket securedto the frame and having outwardly directed pivot points, a pivot ,bar secured to the lever and bearing on said points andprovided with oppositely directed arms, and

a pair of oppositely directed springs having free ends bearing upon the pivot bar arms and their other ends being secured to the bracket.

2.; An electric loud speaking receiver unit, comprising a permanent magnet having poles located in proximity to each other, a frame secured thereto, a solenoid about one of the poles of the magnet, a diaphragm car ried by said frame, an armaturelever having one end rigidly connected with the said diaphragm and its other end under the influence of the said solenoid pole piece, a bracket secured to the frame and having a groove tn accommodate the lever and provided with pivot points directed outwardly from its outer face, a pivot bar secured to the lever, 7

bearing on said points and having oppositely directed arms extending therefrom upon opposite sides of the lever, and a pair of oppositely directed springs having free ends bearing upon the respective pivot bar arms and the other ends being respectively secured to opposite portions of the bracket.

. In testimon whereof I affix my signature.

GE RGE F. G. HOUGHTON, 

